1. Field of the Invention
The invention relates to a method for testing a component part of an aircraft, in which at least one first test value of the component part of the aircraft is determined. The invention also relates to a device for testing a component part of an aircraft, said device comprising a measuring arrangement which is suitable for determining at least one test value for at least one first test parameter.
2. Discussion of Prior Art
Component parts of an aircraft, such as structural elements or systems or groups of systems, which are required for the functional capacity of the aircraft, are tested during development or as a matter of routine. The more relevant such a component is to safety, the more comprehensive are the test protocols. In particular, the number of test parameters rises here in order to achieve the most comprehensive and reliable result possible in terms of the functional capacity of the component part. It has been found that the selection of the test parameters is key for the test result and the validity of the test result.
An example of a component part of an aircraft may be the power supply of the aircraft. The power supply is composed of one or more current sources, consumers and a distribution system. The distribution system comprises cables and junction points. The consumers are connected to the cables and can be provided with a battery or a capacitor in order to bridge short power failures. If the functional capacity of the entire power supply or a part thereof is to be tested, amperages or voltages applied to a specific location of the cable are thus considered as test parameters. These applied amperages or voltages can be used to test the power supply for interference currents or interference voltages. A large number of interference points and therefore test parameters are revealed merely on the basis of the length of the cables in an aircraft. Further, a test parameter may be an externally induced interruption of power at a specific location. Furthermore, the amperage at a consumer or the functional capacity thereof can be considered as a test value.
A test may therefore be, for example, the amperage of the cable applied to the location X of the cable (test parameter T1), an interruption at the location Y of the cable (test parameter T2) and the amperage applied to the consumer V1 (test parameter T3). Test values, which can be determined on the basis of the test parameters T1, T2 and T3, are, for example, the actual amperage at the location X (test value TW1) and the amperage at the consumer V1 (test value TW2). For example, a test result is whether or not the network has a fault. This can be determined from the test values.
Many such test parameters and test values ought to be determined due to the size of the power supply of the aircraft (for example the length of the cables and possible interruption points). This is not possible for time and cost reasons, and therefore the test of the power supply is limited to relevant test parameters and test values. Test parameters can be determined by a random generator. This approach has the disadvantage that the determined test parameters and test values may not have the desired validity. Alternatively, tests can be carried out step-by-step. The efficacy of this approach however is highly dependent on the step increment, and the determination of the step increments is influenced by the experience of the tester.
In modern electronic component parts of an aircraft there are a large number of possible stimulation points (inputs) when testing said component parts. In order to rule out all potential faults of such a component part, it would be necessary to generate the full combination of value pairs for all inputs, to feed this to the component part and to check for fault-free behavior. This is not feasible in practice due to the high number of potential test parameter combinations. Pairwise testing however, which is used to reduce the inputs, is only effective for software tests, in which the majority of faults are dependent on just one input variable, as proven statistically.
DE 69028 872 T2 describes a method for diagnosing the operation of an electronic control system, without requiring a representation of the system in the form of detailed analytical model. Used for this purpose is a pattern recognition system, which uses data obtained by a data acquisition unit, for example data of an engine, to detect engine faults. US 2011/0178967 A1 is concerned with a diagnostic system that automatically analyzes test data to identify characteristics of a component production process. By means of a tester, measurements are made on a component part. US 2006/0061368 A1 discloses a method for determining a cable length or impedance, in order thereby to determine the functional capability of lines, for example in an aircraft. U.S. Pat. No. 5,874,672 A describes a method for measuring the distribution of ice on a surface of an aircraft. U.S. Pat. No. 5,774,376 A describes a method for monitoring, measuring or localizing structural damage to the mechanical structure, such as for example a wing of an aircraft.